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Volume 22, Issue 3
Displaying 1-8 of 8 articles from this issue
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Ichiro AOKI1994 Volume 22 Issue 3 Pages 159
Published: March 29, 1994
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSDownload PDF (123K) -
Tatsuo OKADA, Mitsuo MAEDA1994 Volume 22 Issue 3 Pages 160-171
Published: March 29, 1994
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSLaser spectroscopic technique has been widely applied to dignose in-situ behavior of particles and physical quantities in a variety of industrial fields such as material processing, fluid engineering, combustion and so on.This paper reviews the application of laser spectroscopic diagnostics into a pulsed-laser deposition of high temperature superconducting thin films, which has been recognized as a new and potential method for high quality thin film fabrication.View full abstractDownload PDF (1481K) -
Hiroshi FUKUMURA1994 Volume 22 Issue 3 Pages 172-182
Published: March 29, 1994
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSLaser ablation of polymeric materials sensitized with aromatic compounds has been studied with various time-resolved measurement techniques. Nanosecond imaging revealed the time scale of solid polymer ejection. Transient thermal expansion of polymer was unveiled by a newly developed interferometric method. Time-resolved absorption and emission spectroscopies showed that aromatic sensitizers hardly decomposed but instead indicated hot domain formation in the polymer matrix. Intact sensitizer molecules were detected by time of flight mass spectrometry, and their velocity distribution suggested that the polymer surface was heated up to around 600 K at the ablation threshold. Light absorption dynamics is explained in terms of the repetition of excitation and relaxation in electronic excited states of sensitizer molecules. The generation of transient hot domain in polymer is considered to lead sensitized ablation.View full abstractDownload PDF (1789K) -
Naglaa El Sayed ALY, Kuniyasu KOH, Keiji NOMARU, Hideaki NIKI, Yasukaz ...1994 Volume 22 Issue 3 Pages 183-187
Published: March 29, 1994
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSHigh resolution laser-induced fluorescence spectroscopy has been applied to investigate the isotope shift and hyperfine constant of high-lying odd-parity levels of the gadolinium atom. The isotope shifts were obtained for seven-transitions and hyperfine constants were determined for three levels of the configuration 4F75d6s7s9D0.View full abstractDownload PDF (413K) -
Sakae IKUTA, Masao TAKAHASHI, Miki TATSUKAWA, Shigeru KAWAGUCHI, Tohru ...1994 Volume 22 Issue 3 Pages 188-196
Published: March 29, 1994
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe automatic tuning control system for the injection-locked TEA CO2 laser was developed. The control algorithm is based on the oscillation delay time (td) which has the minimum value when the cavity is tuned to the frequency of injected beam. The cavity length was adjusted with the speed of 0.9 microns per minute by moving the postion of the rear mirror so that the td is controlled to be minimum value by the computer. As the consequence, more than 97 percent of output laser pulses were maintained to oscillate in single longitudinal mode at repetition rate of 96pps.View full abstractDownload PDF (1029K) -
Yasunori SAITO, Kin Pui CHAN, Dennis K. KILLINGER1994 Volume 22 Issue 3 Pages 197-202
Published: March 29, 1994
Released on J-STAGE: July 30, 2010
JOURNAL FREE ACCESSA 2.1 μm “eye-safe wavelength”, 25mJ/pulse (A/O Q-switching), 90ns/pulse Ho lidar systemhas been developed to measure atmospheric extinction coefficients, α, and backscatter coefficients, β. Range esolved values of α and β were obtained at ranges covering up to 1.5km forsevera 124 hour periods. The average values of α were on the order of 10-3 to 10-4m-1 and β values were estimated on the order of 10-5 to 10-6 m-1 sr-1. The variation of β as a function ofrange was small during the period from night to early morning, but increased significantly duringthe later daytime hours. The values of β were somewhat higher from midnight to earlymorning than just after sunrise and then gradually decreased. β values exhibited good correlation with the atmospheric humidity. From these observations it was confirmed that thelidar system developed is a powerful apparatus for remote sensing of the atmosphere.View full abstractDownload PDF (611K) -
Minoru DANNO, Hiroaki SHIMAZUTSU, Tetsuya IKEDA1994 Volume 22 Issue 3 Pages 203-212
Published: March 29, 1994
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSMicrowave discharges for excitation of CO2 laser have been investigated. A resonant microwavecavity (2.45 GHz) has been employed to get high power laser operation. Laser experimentsusing a system composed of fast axial gas flow and axial electric field parrallel to the laserbeam have been performed. Both electric field distribution and resonant frequency of thecavity calculated by using the SUPERFISH were compared with the results of the measurements.Homogeneous discharges caused by the resonance of TM010 mode was obtained usingcylindrical cavity with reentrant type tuners on the both end plates. The laser output of 259 Wand the efficiency of 14% were obtained from a newly developed two-cavity CO2 laser module.View full abstractDownload PDF (1119K) -
Jun ONOE, Toshiyuki OYAMA, Kazuo TAKEUCHI1994 Volume 22 Issue 3 Pages 213-215
Published: March 29, 1994
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSFormation of C60 from the photochemical reaction of a BCl3 and C6H6 gas mixture with a TEA CO2 laser was observed with fast atom bombardment (FAB) mass spectrometry. Thisreaction provides a new way to form fullerenes without conventional plasma reactions ofgraphite such as with the laser vaporization and arc discharge methods.
We demonstrate here the possibility that photochemicalreaction induced by the TEA CO2 laserlight produces C60 from gas phase, unlike theconventional methods.View full abstractDownload PDF (263K)
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